Class: Puppet::Context::Stack Private

Inherits:
Object
  • Object
show all
Defined in:
lib/puppet/context.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Internal implementation of the bindings stack used by Puppet::Context. An instance of Puppet::Context::Stack represents one level of bindings. It caches a merged copy of all the bindings in the stack up to this point. Each element of the stack is immutable, allowing the base to be shared between threads.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parent, bindings, description = '') ⇒ Stack

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Stack


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# File 'lib/puppet/context.rb', line 149

def initialize(parent, bindings, description = '')
  @parent = parent
  @bindings = parent.bindings.merge(bindings || {})
  @description = description
end

Instance Attribute Details

#bindingsObject (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.


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# File 'lib/puppet/context.rb', line 147

def bindings
  @bindings
end

Instance Method Details

#lookup(name, &block) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Lookup a binding in the current stack. Return the value if it is present. If the value is a stored Proc, evaluate, cache, and return the result. If no binding is found and a block is passed evaluate it and return the result. Otherwise an exception is raised.


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# File 'lib/puppet/context.rb', line 161

def lookup(name, &block)
  if @bindings.include?(name)
    value = @bindings[name]
    value.is_a?(Proc) ? (@bindings[name] = value.call) : value
  elsif block
    block.call
  else
    raise UndefinedBindingError,
          _("Unable to lookup '%{name}'") % { name: name }
  end
end

#popObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Pop one level off the stack by returning the parent object.


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# File 'lib/puppet/context.rb', line 176

def pop
  @parent
end

#push(overrides, description = '') ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Push bindings onto the stack by creating a new Stack object with `self` as the parent


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# File 'lib/puppet/context.rb', line 184

def push(overrides, description = '')
  Puppet::Context::Stack.new(self, overrides, description)
end